Fluid-translating device



" H. F. SCHMIDT.

v mum TRANSLATING DEVICE.

APPLICATION FILED SEPT-14, 1914- RE'NEWE'D DEC. 30, 1921. 1342 1 %5 Patented July 4 19220 2 SHEETSSHEET 2.

HIS ATTORNEY IN FACT cairn res ear-ear car es.

I HENRY F. SCHMIDT, OF SWARTHMORE, PENNSYLVANIA, ASSIGNOR T0 WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

menace.

Application filed September 14, 1914, Serial No. 861,635. Renewed December 30, 1921. Serial No. 526,033.

To all whom it m (23 concern:

Be it known that I, HENRY F. SCHMIDT, a citizen of the United States, and a resident of Swarthmore, in the county of Delaware and State of Pennsylvania, have made a new and useful Invention in Fluid-Translating Devices-of which the following is a specification.

This invention relates to fluid translating devices and particularly to devices for maintaining a high vacuum within a condenser or similar apparatus.

An object of the invention is to produce a fluid translating device of the kinetic type in which means are employed for maintaining the operation of the device substantially constant for practically all varying conditions.

A further object is to produce a fluid translating device employing the kinetic or velocity energy of the motive fluid delivered to it in transferring fluid from a region of lower to a region of higher pres-I sure, which automatically adjustsitself to variations in the quantity of fluid conveyed, thus preventing fluctuations of pressure in either the region of higher or lower pressure.

These and other objects, which will be made apparent throughout the further description of the invention, are attained by means of apparatus embodying the features herein described and illustrated in the draw ings accompanying and forming a part of this application.

In the drawings, Figure 1 is a diagrammatic sectional view of an ejector embodying my invention.

Figure 2 is a corresponding view of a modified form of apparatus embodying my invention.

Fig. 3 is a diagrammatic sectionalview of a relay mechanism which may be employed in connection with the apparatus disclosed by either Fig. 1 or Fig.

Fig. 4 is a sectional view of an arrangement of nozzles which be employed in connection with the apparatus disclosed by either Fig. l or Fig. 2.

My invention broadly consists in providing an ejector in which means are employed for varying the effective area of the throat of the diffuser, whichforms a part of the Specification of Letters Patent.

Patented July 4L, i922.

ejector, in response to variations in the amount of flu d or other medium, to be ejected or compressed, delivered to the diffect the results which would be accom plishedby reshaping the walls of the throat to correspond tothe varying conditions of fluid flow through the diffuser.

- In Figure 1, I have illustrated an embodiment of my invention employing two ejectors operating in series, which are generally indicated-by the numerals 3 and i. The ejector 3 under normal conditions operates' as an accelerating ejector and delivers the fluid or medium, to be ejected or compressed, to the ejector 4. The ejector 3, as illustrated, includes a combining and suc. tion chamber 5, provided with a port 5, adapted to'communicate with a receptacle to be evacuated, or with the region of lower pressure from which fluid is to be compressed, to a region of higher pressure. As illustrated, the ejector is also provided with a plurality of expansion nozzles 6, receiving motive fluid from a source of supply, through a' port 7 and a communicating chamber 8. These nozzles are preferably inclined towards each other at their discharge end, so that they discharge jets of fluid through the combining and suction chamber 5 and into a diffuser 9, which communicates with the chamber 5 and forms a part of the ejector 3. The nozzles 6 are preferably so arranged with relation to each other that the streams of fluid discharged by them unite' to form a single stream at .the throat 10 of the diffuser 9.

space into whichit is desired to compress the fluid or medium from the chamber 5.

' different positions in response to variations in the amount of fluid or medium to be compressed, for the purpose of-varying the amount of fluid delivered through the nozzle 11. As illustrated. this is accomplished by providing an operating piston 15 for the movable portion of the ejector l, which is located in a cylinder 16. The pressure existing in the chamber 5, or in the passage 24 communicating with it, is transmitted to one end of thecylinder 16, as for example, below the piston 15, by means of passage 17. The other end of the cylinder is exposed to any pressure above that existing in the chamber 5, such for example, as atmospheric pressure, and motion of the piston in response to a preponderance of atmospheric pressure over that below the piston is opposed by a coiled spring 18 shown as lo cated in the cylinder and acting upon the piston.

.By properly proportioning the tension of the coiled spring, with relation to the area of the piston, the piston will move in response to variations in the pressure trans-- mitted through the pipe 17, so as to proportion the delivery of motive fluid through the nozzles 11 in response to variations in the quantity of fluid or medium discharged from the diffuser 9. so that the throat 21 of the diffuser 13 will always be completely filled with fluid, thus preventing upsetting or a breaking down of the pressure at the outlet of the diffuser to that existing in the chamber 5.

The operation of the apparatusis as follows: The fluid discharged from the nozzles 6 entrains fluid or medium existing in the chamber 5 and moves it through a diffuser 9, in which the velocity of. the combined fluidor'media is partly reduced, thereby performing a portion of the work of translation from the chamber 5 to the outlet of the difluser 13. The combined fluid or media discharged from the diffuser 9 is sub jected to thelentraining action of the motive fluid issuing from the nozzle 11, and is moved by the fluid into the throat 21 and through the diffuser 13, in which the work of .translation is completed. hen the amount of fluid or medium to be compressed is reduced to such an extent that the throat- 21 is not completely filledwith fluid, the piston 15 Will operate to increase the opening of the nozzle 11, thereby increasing the amount of motive fluid delivered for the purpose of more completely filling the throat 21 and aiding in maintaining a greater difference of pressure between the chamber 5 and the outlet of the diffuser13.

In Figure 2, I have illustrated an apparatus in which means are employed for in effect shifting the effective throat of the ejecting device from one positionto another,

dependent upon the amount of medium to of fluid traversing them under normal conditions.

The e ec-tor-3 includes a combmingand suction chamber 5", delivery nozzles 6' and a diffuser 9, which delivers fluid to the combining tube 12 of the ejector 1'. This latter ejector includes an annular row, or a single annular nozzle 11, and a convergent divergent diffuser which may be described as a converging combining tube 12 and a diverging diffuser 13. Ports are located around the combining tube 12 at a point adjacent to the throat 21" of the diffuser 13. These ports are adapted to communicate, under certain conditions, with the suction and combining chamber 5', through a pipe or passage 2%. a pipe or passage 25, an annular chamber 26 and passages 27 and 28. These latter passages are movable with relation to each other, so as to control communication between the ports 23 and the pipe 24. As illustrated, the combining tube 12', the diffuser tube 13 and the outer annular wall of the nozzle 11 are integrally formed or connected together and are movable for the purpose of controlling the discharge area of the nozzle 11 and communication between the passages 27 and 28. For this reason the passages 28 are so formed that they move with the outer annular-Wall of the nozzle 11..

In carrying out my invention as embodied in the apparatus illustrated in Figure 2, I

contemplate reducing the amount of fluid delivered through the annular nozzle. 11 as the pressure in the chamber 5 diminishes, or as the amount of medium to be compressed is reduced. 1 also contemplate increasing the amount of fluid delivered through the nozzle 11f as the pressure in the chamber 5 increases, or as the amount of fluid to be compressed increases, and when a predetermined pressure is attained in the chamber 5, to place the ports 23 in communication with that chamber, so that the two ejectors 3 and 4 will operate in paralle lwith relation to the chamber 5'in removing or compressing fluid from the chamber 5 to the pressure existing at the outlet ofthe diffuser 13. This is accomplished by providing an operating piston '28 which is adapted to shift the combined tubes 12', 13 and the annular wall of the nozzle 11 in response to variations in the pressure existing in the chamber 5.' The.

, sponse to the higher pressure is opposed by a coiled spring 32-, which is shown as 10- cated in cylinder 29 and acting against the piston 28% By properly proportioning the tension of this spring with relation to the area of the piston, the piston will operate to vary the delivery of fluid through the nozzle 11 and will control communication between the ports 23 and the chamber 5 so as to maintain a substantially constant amount of fluid passing through the throat 21 of the difluser'13. By this arrangement, upsetting is prevented and the delivery of motive fluid is so proportioned that as the amount of fluid ormedium to be compressed diminishes, the supply of mo may be employed'which willbperate in response to the variations in the pressure within the chamber 5, to control theoperation of a more powerful motor operatively connected tothe combining tube 12, the difius'er l3 and" annular nozzle wall 11. In Fig- 3, I have illustrated such a mechanism. As shown the pipe 31 is connected to a cylinder 33. similar to the cylinder 29 in every respect except that the piston rod extends through the bottom of the cylinder, instead ofthetop, and is connected to a pilot valve 34. The pilot valve 34 is adapted to control the delivery of actuating fluid to and from the cylinder 29 so as to'cause thepiston 28 to move in response to variations in pressure in the pipe 31. I-have' also shown a dash pot 35 connected to the piston 28 for preventing a response on the part of the latter to minor and discontinuous pressure fluctuations. It will also be apparent that/while I have shown but two embodiments of my invent-ion, it'will be understood that the apparatus is merely illustrative and that various changes, substitutions, omissions and additions may be made without departing from the spirit and scope of the invention as set forth by the appended claims.

In my copending application, serially numbered 861,630, filed Septemberl i, 1914:, and entitled Fluid translating devices, I have illustrated and claimed an ejecting apparatus consisting of a diffuser communicating with the source of medium to be expelled, a nozzle for delivering expelling or motive fluid into and through the diffuser, and means responsive to variations in the pressures encountered within the ejector of the amount of medium to be ejected for varying the effective area of the nozzle. The apparatus therein illustrated is a two stage ejector in which the first stage' includes the motive fluid delivery nozzle and'the diffuser above described, and the second stage includes a diffuser and an annular nozzle or annular series'of nozzles for delivering expelling or motive fluid into and through the second diffuser. The second diffuser communicates with and receives fluid and medium expelled from the first mentioned difl'user.

In my copending application serially numbered 861,633, filed September 14:, 1914 and entitled Fluid translating devices, I have illustrated, described and claimed a single stage ejecting device communicating with a source of medium to be expelled, and a nozzle for delivering expelling or motive fluid through the diffuser. The nozzle is capable of movement toward and away from the inlet end of the diffuser and this movement is controlled by pressure variations within the ejecting device. Means are also disclosed and claimed for varying the effective throat of the movable nozzle in response to variations in the pressures encountered within the "apparatus.

In my copending application serially numbered 861.634, filed September 141, 1914, and entitled Fluid translating devices, I have illustrated, described and claimed an ejecting device provided with a passage from which a medium is to be exhausted communicating with a diffuser through which the medium from the passage is expelled. A

fluiddelivery nozzle delivers expelling fluid through the diffuser and a means responsive to variations in the amount of medium entering the passage is provided for controlling direct communication between the diffuser and the passage. I have further il ustrated and claimed a two stage ejector in which both stages are provided with inlet members capable of being placed in communication with the source of medium to be expelled. The first'stage is shown in open communication with the source of medium to be nexpelled,whereas the second stage is provided with ports lo throatof its con"- and criminunica l substantially at the g diverging difiuser with the source of medium to be expelled through a passage which in effect forms a bypass around the first stage. This passage is provided with a valve which operates in response to variations in pressure at the throat of the second stage fluid to the second ejector.

2. In combination in an apparatus of the character described, a passage receiving fluid to. be ejected, an e ector communicating with said passage and adapted ,to expel fluid fromthe passage to a second ejector, a second ejector receiving the fluid transmitted from the first ejector, and means, responsive to variations in-the mount of fluid received, for proportioning the delivery of motive fluid to the second ejector.

3. In combination in an apparatus of the character described, a passage receiving fluid to be ejected, an ejector-for expelling fluid from said passage, a combining tube for receiving fluid from said ejector, a'diff'user communicating with said combining tube, means for delivering a jet of impelling fluid intothe combining tube and the diffuser, and means for controlling the .fluid delivery means in response to variations in the amount of the medium entering said passage.

4. In combination in an apparatus of the character described, a passage receiving fluid to be compressed, means for partially compressingfluid from said passage, and an ejecting device for receiving fluid from said means, and means responsive to variations in the amount oljfiuid entering said passage, for controlling the operation of the ejecting device.

5. In combination in an apparatus of the 'character described, a passage from which medium is to becompressed, a diffuser through which medium from said passage [is adapted to. pass, a fluid delivery nozzle for delivering impelling fluid through said diffuser, and means responsive to variations in the amount of medium entering said passage for shifting the position of said diffuser relatively to said nozzle. l

6. In combination in an apparatus of the character described, a passage from which medium is to be expelled, means'for.'partially compressing medium withdrawn from said passage, a diffuser into whichsaid' means discharges, a motive fluid nozzle for delivering motive fluid into and through the diffuser, and means responsive to variations in the amount of medium entering said passage for controlling the delivery of motive fluid through said nozzle, and direct communication between ports formed in said diffuser and said passage.

7. In combination in an apparatus of the character described, a passage from which medium is to be exhausted, a movable diffuser having a port formed therein and communicating with said chamber, a nozzle for delivering expelling fluid into and through the diffuser, and means whereby movement of the diffuser controls said port.

8. In combination in an apparatus of the character described a passage from which medium is to be ex austed, a diffuser movable in response to variations in-pressure within said passage, and having a port therein controlled by the movements thereof for. controllin direct communication between said di user andsaid passage, and a nozzle for delivering motive fluid through said diffuser.

9. An ejector comprising a passage from which motive fluid is to be ejected, a diffuser communicating with said passage and movable to different longitudinal positions,

and a nozzle for delivering motive fluid into and through said diffuser.

10. In combination in an ejector, a motive to different nozzle.

11. An ejectin apparatus comprising a chamber from w ich medium is to be exhausted, means for partially compressing the medium, means for completing the compression of the medium, and means responsive to pressure variations within said apparatus for imposing the. entire work of compression on one of said compressing means.

12. In combination in an apparatus of the character described, an ejector communicating with a source of fluid to be ejected,'a second ejector receiving the fluid discharged from the first ejector and means responsive to variations in pressure conditions for controlling the delivery of motive fluid to the second ejector.

13. In combination in an apparatus of the .tially compressed-medium from said means and movable to establish direct communipositions to vary the area of said fluid delivery nozzle, and a diffuser movable cation with said passage other than through i said means.

14. In combination in an apparatus of the character described, a convergent divergent diffuser having an opening formed'nearther" throat thereof and movable longitudinally,

to control the effective area of said opening.

15. In combination in an'apparatus of throat and the delivery of motive fluid 10 through said nozzles.

In testimony whereof, I have hereunto subscribed my name this 21st day of August, 1914. i

" HENRY F. SCHMIDT.

Witnesses:

C. W. MOGHEE,

E. W. MoCALLIsTER. 

